1. Technical Field
This invention relates generally to spark ignition devices, such as spark plugs for internal combustion engines, and more particularly to ground electrodes attached to a metal shell of the spark ignition device and to their method of construction.
2. Related Art
Modern automotive vehicles are required to meet increased power, low fuel consumption, and low exhaust emissions requirements, thus resulting in an increase in temperature of burning atmosphere in the engine. Therefore, spark ignition devices are subjected to increased temperatures, and in turn, have exhibited a reduced life in use. Accordingly, any improvements in promoting heat dissipation of the spark ignition device, particularly in the region of the ground electrode firing tip, is welcomed to prolong the potential useful life of the spark ignition device.
In addition, in accordance with known processes, the ground electrode is manufactured having an excess amount of ground electrode material surrounding a firing tip of the ground electrode. The presence of the excess ground electrode material about the firing tip decreases the ability of heat to dissipate from this region of ground electrode, thereby having a deleterious effect on the ground electrode and firing tip thereon. The excess material results largely due to the known mechanical trimming processes used to shape the region about the ground electrode firing tip, whether a straight or tapered configuration is mechanically cut adjacent the firing tip. Given mechanical cutting processes are typically employed, a predetermined amount of the ground electrode material must remain between an outer side periphery of the ground electrode and the firing tip to avoid damaging the attachment region of the ground electrode and/or the firing tip.
A spark ignition device constructed in accordance with this invention addresses these and other issues, as will be apparent to one having ordinary skill in the art.